Shallow-water (intertidal) Oyster Reef Mapping

Conservation & Management Challenges:

Oyster reefs are one of the most important environmental and economic resources within the coastal regions of the United States. Although oyster reefs in deeper water have been mapped, the extent and condition of intertidal reefs has not been sufficiently inventoried in most states. Understanding the geographic extent and condition of intertidal oyster reef and shell bottoms is important for assessing parental stock and to determine potential recruitment bottlenecks for oysters within an estuary. These intertidal areas have traditionally served as a sanctuary from commercial harvest pressure due to closures, safety, and operational barriers preventing the harvesting of oysters in shallow water. The location and extent of intertidal oyster resources is extremely limited for most of the coast of Louisiana and Texas; their contribution to overall oyster population dynamics is considerable, but poorly understood. Adequate reef mapping will inform ongoing biological planning and restoration efforts.

Research Overview:

Economically, oysters rank seventh in overall landings by ex-vessel price in the United States. They also provide significant environmental services including water filtration, protection of seagrass beds and salt marshes from waves, and forage for some invertebrates and fish. American oysters are unique in that they effectively create an important habitat type through shell deposits, providing their own habitat as well as for other species including numerous marine organisms, commercially and recreationally important finfish, and wading birds like the American Oystercatcher. This project will identify and map selected shallow and intertidal oyster reefs and shell bottom at selected sites along the Texas coastal zone (West Bay and Christmas Bay, where extensive shallow reefs have been detected in the past). Side scanning sonar images will be digitally processed to produce a seamless and geometrically corrected mosaic of images for precise mapping of reefs. Digital cameras placed on low-budget drones will also collect high-resolution images at selected sites to evaluate the ability to map intertidal reefs at reasonable costs. In addition to mapping of selected sites, this project will develop consistent protocols for the mapping and classification for intertidal oyster reefs using both side scan sonar and drones equipped with high-resolution cameras.